In recent years conventional wood frame building material has increased in expense while the quality of that wood has fallen and forest supplies dwindle. Such is the consequence of over consumption and environmental regulations, as well as restrictions on logging intended to protect the forests. Those factors give incentive to the use of alternative building materials, such as steel. In reducing demand for wood, steel thus may be regarded as being environmentally friendly.
Readily erectable economic building systems and elements thereof of a wide variety, which use steel as the frame material, have been known to the prior art, including those building systems described in U.S. Pat. No. 4,599,748, entitled Pre-Formed Building Systems, granted Dec. 24, 1985, to Dennis E. Ressel, the present inventor, hereafter sometimes referred to as the Ressel Patent. As taught in the Ressel Patent, steel frame panel subassemblies may be preformed in the factory and moved to the building site where the building frame is assembled. Buildings of various sizes can be assembled from combinations of several standard size panel assemblies on site on a prepared concrete foundation, easily and economically, usually by relatively unskilled labor. Those persons bolt together the various panels to complete the buildings skeletal frame and then follow with the siding and other detail work to complete the building. Building structures constructed in accordance with the teachings of the Ressel Patent are found effective and extremely strong.
A structural feature of the prior Ressel building system is the inclusion of square sheets of material, wood sheathing, in the panel subassemblies. The sheathing is mounted at the job site to the vertical members of the wall panel subassemblies using sheet metal screw type fasteners. Such sheathing enhanced the rigidity of the associated panel subassembly, particularly, preventing distortion of the subassembly's rectangular shape by shear forces applied to the panel subassembly while the bottom of the subassembly is firmly anchored to the concrete foundation. As those skilled in the art appreciate any shear force, as could be caused by high winds hitting a building structure, tends to stress the rectangular shape of an anchored rectangular frame to that of a rhombus or parallelogram. If the rectangular shape is not sufficiently rigid, the shear force could cause failure of the rectangular frame. The sheathing also provides some slight advantage in insulating the structure. Although that additional strength is desired in many instances, the sheathing is not free of cost.
The additional on site work required to assemble the sheathing and the added material that the manufacturer is required to procure and truck to the building site is viewed as a cost disadvantage. The present invention improves upon the prior wall panel assembly by eliminating the need for such sheathing, while retaining adequate shear resistance, a decided advantage. The present invention improves upon the subassembly structure illustrated in the Ressel Patent in one respect by integrating therein additional bracing structure to adequately resist shear force in the absence of the sheathing. Fabricated entirely in the factory, the improved wall panel subassembly provides substantial overall savings in weight, material costs, shipping costs, and on site labor costs.
A second characteristic of the building systems described in the Ressel Patent is the inclusion of the double vertical support column. That is, separate posts formed from steel tubing were welded together and anchored into place on the foundation to create additional support to the buildings' subassemblies. Primarily, the wall panel subassemblies are assembed and anchored to the foundation, thereafter, the posts are connected to and aligned with the vertical members of those wall panel subassemblies wherein the double vertical support column are aligned with the juncture of two panel subassemblies. The foregoing system thus requires separate assembly steps. It also uses more expensive materials, since the tubing material is more expensive, as example, than a U-shaped channel member. An added advantage to the present invention is that such additional support columns are essentially eliminated as an independent element. The function of that post is instead integrated into the wall panel subassembly, suitably as channel members. By bolting a panel subassembly to the foundation, the post are automatically positioned on the foundation and need not be separately bolted thereto. The invention, thereby eliminates a required on site building step, a decided cost advantage.
Accordingly, an object of the present invention is to provide and improved factory assembled rigid wall frame subassembly that may be produced at lower cost and that allows a building structure to be assembled more easily and quickly than heretofore.
Another object of the invention is to provide an improved building structure, in particular a multi-story building structure, of the partially factory preassembled type that incorporates the novel wall frame subassembly.
A still additional object is to provide a building structure that minimizes and/or avoids the use of separate individually mounted support columns and to provide a panel assembly which integrates the function served by those support columns whereby the building frame structure can be assembled more quickly and easily heretofore.
While the present invention improves upon the building system described in the Ressel Patent, the invention features elements and techniques in common therewith. The Ressel Patent contains description of assembly techniques and illustration of building systems that are useful as: background; an aid to understanding and description of the present invention. Accordingly, the text and illustrations of the Ressel Patent, U.S. Pat. No. 4,559,748, are referred to and incorporated herein in its entirety and forms part of the disclosure of this specification.